This paper reports a study of public order policing during a major anti-capitalist riot. Officers were observed in the control room at New Scotland Yard throughout the event, and the two senior commanders were interviewed. The analysis demonstrates both the importance and the complexity of accountability concerns in determining police decisions. Officers are simultaneously accountable to multiple audiences who place different and sometimes contradictory demands upon them. Moreover officers in different positions may be subject to different accountability concerns. These lead to different action preferences that can create intra-organizational conflict. For instance, senior commanders were reluctant to use tactics that the general public and other external audiences might view as escalating the conflict or endangering the safety of protestors. In contrast, junior officers were less concerned with external audiences and supported these tactics as necessary to protect police safety. The theoretical significance of these findings is framed in terms of the SIDE model.